AVRDUDE problem on uploading

Hi everyone. Apologies if this has already been discussed and resolved, but I could not find any answer which would solve my problem.

Getting the following error message when uploading:
Arduino: 1.8.3 (Windows 7), Board: "Arduino/Genuino Uno"

Sketch uses 1888 bytes (5%) of program storage space. Maximum is 32256 bytes.
Global variables use 188 bytes (9%) of dynamic memory, leaving 1860 bytes for local variables. Maximum is 2048 bytes.
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_recv(): programmer is not responding

avrdude: arduino_read_sig_bytes(): (a) protocol error, expect=0x10, resp=0xb0
avrdude: error reading signature data for part "ATmega328P", rc=-3
avrdude: error reading signature data, rc=-1
avrdude: error reading signature data, rc=-1

This is happening for the firs time. All was working fine with the same board and cables.

Board - Arduino Uno - ATMEGA328P-PU

Arduino IDE 1.8.3
Windows 7

Connected via USB, shown as "Arduino/Genuino Uno on COM8"

Power (green) led is on when connected
RX and TX Leds are blinking during upload

Please HELP!!!

Anything connected to pins 0 or 1 on the Arduino?